Page 10 - Nutrinsight-3

NutrInsight • Do we need dietary polyphenols for health?
Blood Bioavailable metabolites (nM concentrations)
UGT SULT COMT
Small intestine Interindividual variability Colon UGT
SULT COMT
Flavan 3-ols Stilbenes food
Diffusion
LPH MRP Intestinal lumen food FOOD
Lignans food Proanthocyanidins
food
Flavanone rutinosides
food food
Anthocyanins
food Microbiota metabolism
Flavonol rutinosides
food food Flavonol glycosides
food
food Hydroxycinnamates food Isoflavones food
food
Ellagitannins
food food
Alkylresorcinols
Figure 4: Polyphenols transit and absorption in the GI tract
Polyphenol interactions with some other food constituents, gut microbiota and intestinal cells. Sources of interindividual variability in polyphenol absorption and metabolism. Abbr. LPH (Lactose-phloridzin hydrolase),
UGT (Glucuronyl transferases), SULT (Sulpho transferases), MRP (Multidrug resistance related protein).
Source: From F A. Tomás-Barberán.
• Food matrix and other constituents of the diet
The solubility of the polyphenols in the food matrix they occur, impact their bioavailabity, with the more soluble, e.g. orange flavanones, being the most bioavailable [Vallejo et al., 2010]. Presence of pectins and fibres in the food matrix could increase bioavailability [Richling et al., 2011], as would sugar and oils [Martinez-Huelamo et al., 2011]. Protein, on the other hand, would decrease bioavailability.
As an example, in a study of epicatechin pharmacokinetics in cocoa, Neilson et al [Neilson et al., 2010] showed that in solid chocolate, sugar tended to increase polyphenols bioavailability whereas milk protein appeared to decrease it. On the other hand, in chocolate beverages, bioavailability of polyphenols was higher compared to solid chocolate and nutrients (especially sugars) impact less their bioavailability. This indicates that the physical state of the product as consumed appeared to be the principal factor governing bioavailability.
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